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Carburetor insulator gaskets
Posted by: thumper477 ()
Date: August 12, 2022 11:58AM

should the plastic carb base insulator spacer have thin paper gaskets on both sides of it?I have a Dead #1 cylinder at idle.Compression and spark and valve adjustment ok.If I spray carb cleaner around the base of the secondary carb next to the #1 cylinder,the skip goes away and engine runs smooth.I do not think the spacers had any gaskets on them when I took the carbs off to rebuild them,maybe 50+ year old spacers do not seal like new ones or maybe the spacer has a crack in it?Thanks.By the way it is 1965 140 with no idle circuits on the secondarys.



Edited 2 time(s). Last edit at 08/12/2022 12:00PM by thumper477.

Re: Carburetor insulator gaskets
Posted by: RexJohnson ()
Date: August 12, 2022 12:05PM

Put your hand over the top of the carb. If the miss goes away you have a leaking throttle plate. Also check the throttle shaft. The factory only used the plastic spacer. If everything is flat, spacer, carb base and the plastic spacer you don't need paper gaskets.

RJ tools
Salem,Oregon

Re: Carburetor insulator gaskets
Posted by: thumper477 ()
Date: August 12, 2022 12:25PM

Thanks,I will give it a try and report back.

Re: Carburetor insulator gaskets
Posted by: dryenko ()
Date: August 13, 2022 04:43AM

The spacers distort with heat and age.
A flat glass plate and some 120 or 180 grit body work discs stuck to it and be used to flatten them so they will not leak.
If cab base and manifold are also flat.

Bob C aka Dryenko
Dobson, NC 27017

Re: Carburetor insulator gaskets
Posted by: vairmech ()
Date: August 13, 2022 05:01AM

If you put the insulators back on the way they came off they will work just fine. If you turn them over and not watch how you put them back on the carb base will not seal and/or you will break the phenolic again causing an air leak.

Everyone that puts one of those thin paper gaskets on is only trying to cover something up. Those thin paper gaskets also stick to the phenolic and most times it will not come off ruining reusing the phenolic.

As far as your issue, make sure the phenolic is on the way it came off if it didn't break.

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com



Edited 1 time(s). Last edit at 08/13/2022 05:02AM by vairmech.

Re: Carburetor insulator gaskets
Posted by: thumper477 ()
Date: August 13, 2022 08:36AM

Thanks Ken.

Re: Carburetor insulator gaskets
Posted by: thumper477 ()
Date: September 13, 2022 01:43PM

Old phenolic gasket looked good.I felt a little high spot on the carb base.I think it had a small injury from falling off the bench on to the concrete floor.I block sanded the carb base and got it smooth and installed a good different used phenolic gasket.Car runs like a good 140 should run.
on all 6.Thanks to you folks for all the help.Much appreciated.Thumper.



Edited 2 time(s). Last edit at 09/13/2022 01:49PM by thumper477.

Re: Carburetor insulator gaskets
Posted by: Frank DuVal ()
Date: September 13, 2022 02:03PM

Quote
thumper
If I spray carb cleaner around the base of the secondary carb next to the #1 cylinder,the skip goes away

Right there is the proof of a vacuum leak. Glad you found it and fixed the leak.smileys with beer

It doesn't take much of an upheaval in the carburetor base surface to make an issue, does it!winking smiley

Frank DuVal

Fredericksburg, VA

Re: Carburetor insulator gaskets
Posted by: thumper477 ()
Date: September 14, 2022 03:28PM

I'll tell you what,the tiny injury on the carb base was enough to piss off the phenolic gasket to leak!!!

Re: Carburetor insulator gaskets
Posted by: PequotMonza64 ()
Date: September 15, 2022 04:12PM

vairmech Wrote:
-------------------------------------------------------
> If you put the insulators back on the way they came off they will work just fine. If you turn them over and not watch how you put them back on the carb base will not seal and/or you will break the phenolic again causing an air leak.
>
> Everyone that puts one of those thin paper gaskets on is only trying to cover something up. Those thin paper gaskets also stick to the phenolic and most times it will not come off ruining reusing the phenolic.
>

What you are describing there is a defective part, namely the phenolic spacer. They were never designed to be fitted only one way. They were also not expected to last half a century.

If you look at a brand new Holley carb phenolic spacer, you'll see that it comes with two paper gaskets, one for above the spacer and one for below the spacer. These are necessary and prudent to install even on a phenolic spacer that is NOT 50 years old being installed on modern machined surfaces.

Finally, there's no way to know how many times that phenolic spacer has been on and off of a Corvair engine and how many times it has been flipped over the years. And generally speaking, you wouldn't know if the spacer was already leaking before you took off a carb that needed rebuilding.

Glen in Ohio
1964 Monza Sedan Powerglide 110 hp
Low mileage survivor, stock as delivered
Records back to 1967 in Pequot Lakes, Minnesota
Original dealer Mike Turk's in East Liverpool, Ohio
Located in Cleveland, Ohio area





Edited 1 time(s). Last edit at 09/15/2022 04:13PM by PequotMonza64.

Re: Carburetor insulator gaskets
Posted by: Spyderman64 ()
Date: September 15, 2022 05:20PM

I always use them on both sides of the insulator. Can’t hurt, may help. Why not?

Re: Carburetor insulator gaskets
Posted by: Frank DuVal ()
Date: September 15, 2022 05:51PM

I very rarely use the thin insulators. The thicker ones (found in the non-vendor carburetor kits) suck* to put it mildly, usually so tall the mounting studs have little room left for the nuts.

The really thin ones do work to fix flatness issues, but I usually just fix the issues. thumbs up

Phenolic insulator by itself has worked well for 40+ years for me.

Holley sells the phenolic spacers? I just order form our vendors. Used to get GM ones, now get the reproduced ones. Probably made by Holley...

*and the sucking noise is a vacuum leak!grinning smiley

Frank DuVal

Fredericksburg, VA

Re: Carburetor insulator gaskets
Posted by: PequotMonza64 ()
Date: September 16, 2022 10:37AM

Frank DuVal Wrote:
-------------------------------------------------------

> Holley sells the phenolic spacers? I just order form our vendors. Used to get GM ones, now get the reproduced ones. Probably made by Holley...
>

Holley makes them for their big honking 4-barrels, Frank! ;-)

Phenolic is know for its stiffness and its heat insulation properties, but any plastic outgases over time and becomes more brittle. I'm going to shoot some carb cleaner around the base of my carbs and see if any leaks become evident. Maybe I'll buy a couple of new phenolics to have on hand, but I'm done pulling my carbs for this summer.

Glen in Ohio
1964 Monza Sedan Powerglide 110 hp
Low mileage survivor, stock as delivered
Records back to 1967 in Pequot Lakes, Minnesota
Original dealer Mike Turk's in East Liverpool, Ohio
Located in Cleveland, Ohio area


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